When is Jerusalem raised up?
The prophecy of Isaiah 2:1-4 says that the mountain of the Lord’s house will be established in the tops of the mountains. An article by Dr. Seth Erlandsson discusses this and several other prophecies about changes in the promised land, and applies them to the church.  Erlandsson relates these prophecies to the new covenant, and to the new Jerusalem. In Isaiah 2:2, all nations flow to the mountain of the Lord; many will seek to learn about God’s word at Jerusalem.
Erlandsson explained that the new covenant fulfills the old covenant’s promises that were directed to “the House of Israel and the House of Judah.” He wrote:
Jesus and his saving work cast their shadow already in advance on the Scriptures of the old covenant. Therefore Jesus can say of the Scriptures: “It is these that bear witness of me” (John 5:39). “The Law (Torah) is only a shadow of the good things that are coming – not the realities themselves”, writes the author of Hebrews (10:1). The old covenant’s many purity regulations, sacrificial laws and rules for Sabbaths and festivals are a shadow of Christ and His kingdom, teaching that fellowship with God demands total purity, that sin is atoned for and fellowship with God is re-established through the only Pure One, a fellowship which gives rest, joy, peace and eternal life. … “Jesus has become the guarantee of a better covenant” (Heb. 7:22). “The covenant of which he is mediator is superior to the old one, and it is founded on better promises. For if there had been nothing wrong with the first covenant, no place would have been sought for another” (Heb. 8:6-7). “By calling this covenant ‘new’ (Jer. 32:31), he has made the first one obsolete; and what is obsolete and aging will soon disappear” (Heb. 8:13). Those who reject Christ as the fulfillment of the old covenant’s shadows, pictures and promises, have a veil over their heart, according to Paul, so that they cannot see and understand what the old covenant’s Scriptures really say. “Even to this day when Moses is read, a veil covers their hearts. But whenever anyone turns to the Lord, the veil is taken away” (2 Cor. 3:15-16).
The true Israel and Judah to which the promises and prophecies such as Isaiah 2:1-4 apply are not unbelievers, but those who believe in Christ and his promises. Erlandsson wrote:
God’s true Israel does not include both believers and unbelievers. God’s true Israel is not the same thing as the earthly, worldly Israel, but rather is those who are true Israelites or Jews, i.e. those who believe in the LORD’s promises. (Cf. Rom. 2:28-29 and John 1:47). Those who do not say AMEN (i.e. believe firmly) to the LORD and his word of promise have no firmness (lasting peace). Isaiah underlines that with a play on words (Isa. 7:9, Hebrew: taAMINu – teAMENu). Paul, thoroughly trained in biblical interpretation as a scribe and Pharisee, writes: “Not all who are descended from Israel are Israel. Nor because they are his descendants are they all Abraham’s children… It is not the natural children who are God’s children, but it is the children of the promise who are regarded as Abraham’s offspring” (Rom. 9:6-8). The LORD had revealed to Isaiah: “Though your people, O Israel, be like the sand by the sea, only a remnant will return” (Isa. 10:22).
Isaiah’s prophecy that indicates that mount Zion and Jerusalem will be “raised up above the hills” and other similar prophecies about changes in the land should be understood as metaphors for the Kingdom of God. Erlandsson wrote:
Thus it is already made clear in the Old Testament that the messianic Kingdom of God or Kingdom of Heaven is of an entirely different nature than the kingdoms of this world. Just as the Messiah himself, this Kingdom is “from above” (Dan. 7:13f, Joh. 8:23; 18:36). But the metaphors for the Kingdom of the Messiah employ as their point of contrast and comparison the earthly situations that existed during the time of the old covenant.
The prophecies about Jerusalem are to be applied not to the earthly city, but the heavenly one. Erlandsson wrote:
The fulfilment of the old covenant’s promises regarding God’s city Jerusalem and Mount Zion has to do with “a better country – a heavenly one”. Paul writes, “The present city of Jerusalem … is in slavery with her children. But the Jerusalem that is above is free, and she is our mother” (Gal. 4:25-26). This Mount Zion or Jerusalem which according the epistle to the Hebrews is the fulfilment of the prophetic promises is “the heavenly Jerusalem, the city of the living God … the church of the firstborn, whose names are written in heaven” (Heb. 12:22-23). All who receive and trust in the Messiah and his work of redemption, wherever they may live, have come to this true Zion which is called the highest and most prominent of all mountains. This mountain “shall stand firm” (Hebrew: nakon, “unmovable”, „fest gegründet“) (Isa. 2:2).
Erlandsson suggested that the time when mount Zion and Jerusalem are to be raised up is at the coming of the Messiah and his Kingdom. He wrote:
Mount Zion and its temple refer to the Messiah and his Kingdom. Through the coming of the Messiah the promise of blessing “for all peoples on earth” first made to Abraham is fulfilled (Gen. 12:3). Not only a remnant of the earthly Israel will come to the Messiah and receive “the word of the LORD” from him and from his true people. Nay, rather “all nations will stream to it” – to that mountain which is stable and stationary and eternal, the highest and foremost of all mountains. “God promised that he would send his Messiah and that the Messiah’s work would become the most important epoch in the history of Judah and Jerusalem. Because of the fulfilment, the Lord would draw all nations to come and learn of his love for sinners.” And when Christ returns all believers, wherever they live in this world, will be gathered to the new Jerusalem.
Is this correct? Does Isaiah’s prophecy mean that Jerusalem and mount Zion are yet to be raised up? Hebrews 12:22-24 speaks of the heavenly Jerusalem; it is already up in heaven. All believers come to it.
But ye are come unto mount Sion, and unto the city of the living God, the heavenly Jerusalem, and to an innumerable company of angels, To the general assembly and church of the firstborn, which are written in heaven, and to God the Judge of all, and to the spirits of just men made perfect, And to Jesus the mediator of the new covenant, and to the blood of sprinkling, that speaketh better things than that of Abel.
In Revelation 21, John describes the heavenly Jerusalem descending from heaven to the earth. If Isaiah 2:2-3 applies when Christ returns, it would appear to contradict what John wrote:
And he carried me away in the spirit to a great and high mountain, and shewed me that great city, the holy Jerusalem, descending out of heaven from God,
The difficulty vanishes if Jerusalem was raised up as Isaiah 2:3 foretold, in New Testament times, when Jesus ascended to heaven. John said that he saw no temple in the heavenly city; “for the Lord God Almighty and the Lamb are the temple of it.” [Revelation 21:22] The heavenly city John described is the church that Christ is building in the present age. At Christ’s coming at the end of the age the city descends to the earth. Jesus together with all his saints come to establish his reign in the earth, bringing salvation.
1. Seth Erlandsson. Exegetical Study of Isaiah 2:1-4 – The Prophecy and its Fulfilment. Wisconsin Lutheran Quarterly vol. 104/4 (Fall 2007).